Synthesis of Chitosan Oligomers/Propolis/Silver Nanoparticles Composite Systems and Study of Their Activity against Diplodia seriata

Table 2

Assignment of FTIR spectra bands.

Chitosan	Chitosan oligomers	Propolis	Chitosan/propolis	Chitosan/propolis/silver NPs	Assignation
3290	3285		3285	3300	υ(OH) overlapped to υs(N–H) [35, 36]
		2970		2972	C–H bands of aromatic compounds
		2930		2929	υas(C–H) in –CH2 [35]
2867	—	2873		2873	υs(C–H) in –CH3 [35]
1646	1649	1640; 1598		1707	υ(–C=O) of the amide group CONHR in chitosan [36, 38] and υ(–C=O) of flavonoids and lipids, found in propolis [39]/aromatic ring deformations [39]
1568	—		1554	1560	υ(–C=O) protonated amide group [35]; δ(NH3) protonated amine group
1417	1419		1404	1409	δ(OH) [40]
1372	1375	1377		1373	δ(–CH3) [41]
		1334	1341	1333	Typical propolis C–O and C–OH vibrations [39]
1318	1317				υs(–CH3) tertiary amide [35]; ω(–CH2) + OH in-plane deformation
		1284; 1228		1260	υ(C–O–H) [35]
1152	1148		1150	1160	υas(CO) in oxygen bridge resulting from deacetylation of chitosan
		1136		1133	Alkenes bands from propolis (coumaroyl glycerol) [42]
1060	1081	1078	1066	1084	υ(CO) of the ring C–O–H, C–O–C and CH2CO [35, 39]
		1038; 989		1042; 986	Bands from propolis
		920	923	922	Bands from propolis
892	892			872	ω(C–H) of the saccharide structure [35]
		836		835	Band from propolis
			646; 617	656; 615	Typical bands from binary and ternary formulations